With its customer base shrinking, the tobacco industry is seeking alternative products to traditional and profitable cigarettes. The $50 billion-per-year marijuana market will be a tempting takeover target.

While opponents of legalization have long argued that marijuana could serve as a gateway to harder drugs, less attention has been paid to the potential for pot to lead to tobacco addiction among youths. Inhaling smoke into the lungs is an unnatural act that most teens find unpleasant at first, but marijuana may help train them. Smoking a joint means holding the smoke in the lungs as long as possible and then letting it out slowly.

While teens experimenting with marijuana seldom become lifelong users, the same cannot be said of tobacco due to the potent addictiveness of nicotine. Blunts, which combine flavored tobacco leaf wrappers with marijuana, are popular among teens. Studies show that among adults, as many as 90 percent of regular cannabis users also smoke cigarettes, which makes it more difficult to quit. The bottom line is that legalized marijuana could be exploited by the tobacco industry to both retain adult smokers as well as to reverse the decline in youth smoking.

The tide of public opinion is toward legalizing marijuana. After the November election, 28 states allow medicinal use, and California and seven other states permit recreational use. The current federal policy of noninterference with state marijuana laws may transition into nationwide legalization over the coming years.

Since the 1960s, the tobacco industry has been considering ways it might exploit the marijuana market, but it appears to be awaiting federal legalization before a major move into the marijuana business.

The industry’s playbook for asserting dominance over marijuana might begin with their relationship with farmers, who will be motivated to replant their declining tobacco acreage with marijuana as a highly profitable cash crop.

A key advantage of the tobacco industry is its remarkable prowess in advertising, coupled with its enormous multibillion-dollar marketing budget. Tobacco and marijuana can be promoted together as a way to relax and have fun; pot ads could help restore glamour to smoking. Tobacco companies may create marijuana subsidiaries, or extend existing product lines. Marijuana could be sold with Newport cigarettes as menthol-flavored “New Pot.”

The tobacco industry also exerts enormous political influence. It has a long history of contributing to legislators who then support favorable regulations and rules that limit competition. To suppress small marijuana growers, tobacco firms could promote costly testing requirements for pesticide residue and product purity. They may seek to put today’s marijuana dispensaries out of business in favor of the retail avenues they dominate. Under the banner of “protecting children,” they may work to prohibit edible marijuana products.

Tobacco companies have used similar methods to dominate the e-cigarette market, using their control of shelf space in convenience stores and gas stations and marketing muscle. Companies also helped shape new federal regulations that may drive most independent e-cigarette competition out of the market over the next few years.

To prevent Big Tobacco from exploiting legalized marijuana, it will be important for regulators to erect a strong wall between these two industries. States can help lay the groundwork for a future federal policy by prohibiting the sale of tobacco products where marijuana is sold, as California has done. If nationwide legalization happens, it is essential that the tobacco industry is banned from the marijuana market.

Robert K. Jackler is a professor at the Stanford University School of Medicine and principal investigator at Stanford Research into the Impact of Tobacco Advertising. He can be contacted at jackler@stanford.edu.